Drill grinder



1962 E. D. HEWES ETA]. 3,

DRILL GRINDER Filed Jan. 21, 1960 4 Sheets-Sheet 1 INVENTORS ELLSWORTH DAYTON HEWES D BY LAMOND K. BROWNELL Oct. 9, 1962 E. D. HEWES ET AL 3,057,122

DRILL GRINDER Filed Jan. 21, 1960 4 Sheets-Sheet 2 FIG. 2

AN BY LAMOND K. BROWNELL Oct. 9, 1962 E. D. HEWES ETAL 3,057,122

DRILL GRINDER Filed Jan. 21, 1960 4 Sheets-Sheet 3 INVENTORS ELLSWORTH DAYTON HEWES y AND LAMOND K. BROWNELL 1952 E. D. HEWES ET AL 3,057,122

DRILL GRINDER Filed Jan. 21, 1960 4 sheets sheet 4 INVENTORS ELLSWORTH DAYTON HEWES AND BY LAMOND K. BROWNELL nits The present invention relates to grinders, and more particularly to machines for grinding the points of drills.

One object of the present invention is to provide an improved drill grinder for grinding drills of different sizes and different lip angles precisely, and even to the extent of reclaiming badly burned or broken drills.

Another object of the invention is to provide a machine of the character described in which provision is made to insure maximum life of the grinding wheel, with a minimum of wheel dressing.

Another object of the invention is to provide a drill grinder in which the drill holder can be quickly and readily positioned in accordance with the lip angle which it is desired to grind on the tip of the drill.

Another object of the invention is to provide a grinder of the character described which will be compact, simple in operation and construction, and eflicient.

Other objects of the invention will be apparent hereinafter from the specification, particularly when read in conjunction with the accompanying drawings, and from the recital of the appended claims.

In the drawings:

FIG. 1 is a perspective view of a drill grinding machine built according to one embodiment of this invention;

FIG. 2 is a vertical sectional view taken through the longitudinal center line of the machine and showing the grinding wheel, the motor which drives the same, the motor support and its mounting, and the means for effecting the feed adjustment of the wheel;

FIG. 3 is a part end elevation, part sectional view showing particularly the means for adjusting the angle of oscillation of the wheel, and showing fragmentarily, also, the arm that supports the drill holder;

FIG. 4- is an enlarged fragmentary plan view of the drill holder and showing a drill mounted thereon and in engagement with the grinding wheel which is shown only fragmentarily;

FIG. 5 is a side elevation of the drill holder, but with the drill removed;

FIG. 6 is a section on the line 66 of FIG. 7 looking in the direction of the arrows;

FIG. 7 is a fragmentary section on the line 7-7 of FIG. 6 looking in the direction of the arrows;

FIG. 8 is a section taken generally on the line 8-8 of FIG. 4 looking in the direction of the arrows; and

FIG. 9 is a section on the line 99 of FIG. 8 looking in the direction of the arrows.

The drill grinder of the present invention is an improvement on the machine disclosed in Patent No. 2,142,923, granted January 3, 1939.

Referring now to the drawings by numerals of reference, 10 denotes the base of the machine. Journaled in the base 10 on spaced anti-friction bearings 11 and 12 (FIG. 2) is a screw shaft 14. This shaft is held against axial movement relative to the base by a pin 15 which is secured in the base, and which threads into a spacer sleeve 16 that is interposed between the ball bearings 11 and 12. The bearing 12 seats against a shoulder formed on the shaft 14 at the juncture of a reduced diameter portion of the shaft with a larger diameter portion thereof. The ball bearings are held in position on the shaft against 3,057,122 Patented Oct. 9, 1962 ICC axial movement relative thereto by nuts 17 and 18 that thread onto the shaft adjacent one end of the shaft. The shaft 14 is adapted to be rotated by a hand wheel 23 which is keyed to the shaft 14 at this end, and which is held on the shaft by a screw 24. A pin 25 secured in the hand wheel is provided to rotate the same. The hand Wheel is provided with graduations 26 which read against a zero mark formed on the adjoining beveled portion 27 of the base.

The shaft 14 is threaded intermediate its ends into a sleeve 22, and is threaded at its end, opposite from the hand wheel into a nut 21. This nut fits slidably into the sleeve 22 but is keyed against rotation relative to the sleeve. The sleeve, in turn, is keyed by means of the key 23 against rotation relative to the base 10. It is mounted to slide axially in spaced bearing portions 28 and 29 formed in base 10. Surrounding the shaft 14 and interposed between the sleeve 22 and the nut 21 is a coil spring 20. This serves to force the nut axially away from the sleeve 22 to take up backlash between the threaded portion of the shaft and the parts into which it threads.

Mounted on the sleeve 22 to move axially therewith but to oscillate relative thereto is a support 30 for a conventional electric motor 31. The support 30 is formed with a journal portion 32 which surrounds and is journaled on the sleeve 22 intermediate the ends of the sleeve. The sleeve 22 is formed with a peripheral rib 33 and with an adjoining peripheral groove 34. The journal portion 32 of the motor support 30 is held against one side of the rib 33 by a clamp lug 35 which engages in the groove 34 and which is secured to the motor support by a screw 36. This lug 35 serves to transmit axial motion of the sleeve 22 to the motor support.

The journal portion 32 of the motor support is formed with a depending extension (FIGS. 2 and 3). A stop screw 41, which threads into a nut 42 that is secured in the base 10, serves to adjustably limit the swinging movement of the motor support 30 in one direction. This stop 41 may be tipped by a nylon tip 45 to cushion the stoppage of the motor support as it is swung in said one direction. A bumper 43, which may be made of neoprene, for instance, and which is secured to the base 14) by, for instance, a screw 44, serves to limit the swinging movement of the motor support 30 in the opposite direction. The stop 4-1 is adjusted by means of a hand wheel 46 which is keyed to the stop 41, and which is secured to the stop by a screw 47. A pin 48 fastened in the hand wheel is provided to manipulate the same.

The grinding wheel W, which is to be used on the machine, is removably secured to the armature shaft of the motor '31. This wheel is a cup-shaped wheel.

The wheel is surrounded by a guard 50 that is welded, or otherwise fixedly secured, to the housing of the motor 31; and the motor support 30 may be oscillated by a lever 51 which is welded or otherwise rigidly-secured to the guard 50. A knob 52, is provided on the free end of the lever 51 for manipulation of the lever.

Mounted at one end on the base 10 beneath the guard 50 is a supporting arm 55 (FIGS. 1, 2 and 3). This arm is mounted on the base 10 for angular adjustment relative thereto about a vertical axis. Graduations 56 are provided on a plate 57, that is secured between the arm and the base, to permit setting the arm in accordance with the angle of the lip to be ground on the end of the drill. These graduations read against a zero mark 58 on the end of the arm. The arm is adapted-to be secured in any adjusted position on the base by a screw 59 which passes through a washer 6t) and which threads into the bearing sleer e 61 on which the' arm is rotatable. The sleeve 61 is held against rotation relative to the base by a dowel pin 63 or the like.

Mounted in the free end of the arm (FIGS. 6 and 7). Opposite ends of this bushing are formed as races for the ball bearings 66 and 67. The ball bearings 66 and 67 engage races 68 and 69, respectively, secured in axial alignment in a swivel bracket 70 at opposite sides of the arm 55. Race 69 is formed in a block that has a pressed fiit in swivel bracket 70. Race 68 is mounted for axial adjustment in swivel bracket 70 and is threaded along a portion of its periphery to thread toward and from race 69 to control the load on the ball bearings. A lock nut 64, that threads on race 68, serves to lock the race in any adjusted posit-ion.

One end of the swivel bracket 70 is formed with an angularly olfset extremity denoted at 71 (FIG. 1). Mounted within the offset extremity 71 is a rod 72 (FIGS. 4 and which is slabbed off intermediate its ends, as denoted at 73 is FIG. 5. The rod 72 is held against rotation relative to the swivel bracket 70 by a clamping pin 74 which threads into the extension 71 of the bracket, and which engages against the slabbed surface 73 of the rod 72. The pin 74 has a knurled head 75 by means of which it may be manipulated. Mounted on the rod 72 to be adjustable therealong, and to be reversible relative thereto is a supporting member 77. A clamping pin 78, which slides in a milled slot 79 in the supporting member, and which is adapted to be moved manually by gripping its knurled head, can be wedged against rod 72, to lock the supporting member in adjusted position on the rod 72. The supporting member '77 is bored at its free end to receive a rod 80 which serves as a center and support for one end of the drill D, which is to be ground. The centering member 80 is provided with conical centering holes 81 and 82 at its opposite ends, which are adapted to receive the conical ends of drills. These holes are of different diameter and/ or cone angle; and the centering member 80 can be reversed end for end in the supporting member 77 so that the supporting member 77 can support drills of difierent lengths and shanks. The centering member 80 is secured in the member 77 by a setscrew 83.

The drill, which is to be ground, is supported adjacent its opposite end by a chuck, similar to that used in the machine of Patent No. 2,142,923 above-mentioned. The rod 72 carries at the end, opposite that which carries the member 77, a body member 90. This body member is secured to the rod 72 by a clamping pin 91 which threads into the body member 90 and which engages against the fiatted portion 92 of the rod 72. The body member 90 has riveted thereto a pin 93 (FIG. 8), the outer end of which is threaded for the reception of a nut 94. This nut is locked in adjusted position on the threaded end of the pin 93 by means of a setscrew 95 which is threaded through the nut 94 for engagement With the extremity of the pin 93. The pin 93 constitutes a journal for a cam disc 96 which is held on the pin 93 by the nut 94. A spring 97, which is interposed between the nut and the washer 98, that rests in the bottom of the countersunk recess 99 in the hand wheel, resiliently forces the hand wheel inwardly on the pin.

The inner face of the cam disc bears upon a slide plate 100. This plate has an outer ofiset end .101 which constitutes one jaw of a chuck. This plate carries a pin 102 which engages in a cam groove 103 in the inner face of the cam disc 96 as shown in FIGS. 8 and 9. This plate 100 also bears against a second slide plate 104 which in turn bears against the inner face of the body member 90. The plate 104 has an offset end 105 which forms the other jaw of the chuck. The plate 104 carries a pin v106 which extends through a longitudinal slot 107 in the plate 100 and which enters a second cam groove 108 in the underside of the cam disc 96. Cam disc 96 may be rotated by knob 109 which is mounted on a lever 110 that threads into the cam disc. The arrangement is such that rotation of the cam disc 96, by means of the knob 109, effects movement through the medium of the pins 102 :and 106 and the cam grooves 103 and 108 of the jaws 55 is a bushing 65 i 41 101 and toward or away from one another, depending upon the direction in which the hand wheel is rotated.

Each of the jaws carries two screws 111 by means of which jaw inserts 112 and 113, respectively, are secured to the respective jaws. These inserts project transversely from the jaws and are formed to receive and grip opposite sides of the drill, which is to be ground, so that the drill at all times is held in a predetermined position in the chuck.

In operation, the arm 55 is adjusted angularly on the base 10 in accordance with the angle of the lips to be ground on the drill. The grinding wheel support 30 is adjusted rectilinearly along the shaft 14 by rotation of the handwheel 23 to bring the plane of the front face of the grinding wheel to the correct position to grind the desired amount of stock off of a lip of the drill and to bring the lip of the drill into engagement with the face of the grinding wheel. In grinding a drill, the operator oscillates the swivel bracket 70 back and forth by rocking the lever 115 back and forth with one hand by grasping the knob 116, and while feeding the drill into the grinding wheel through manipulation of the handwheel 23. Lever 115 is threaded into swivel bracket 70 and knob 116 is secured to the free end of this lever.

As the grinding wheel rotates on its axis, then, it will grind the stock off one lip of the drill. The swinging movement of the bracket 70 traverses the lip of the drill across the face of the grinding wheel. The angular movement of the bracket '70 is limited by its engagement with the stop blocks 118 and 119 formed integral with arm 55 as indicated in dotted lines in FIG. 7.

The angular relation and the relative positions of the parts are such that the described operation results in grinding at the proper angle and with the correct clearance behind the cutting edge that lip of the drill which is in contact with the grinding wheel.

When one lip has been ground to the required extent, the chuck is loosened and the drill is turned to an angle of to bring the other lip of the drill into grinding position. The micrometer scale 26 affords the means for feeding the drill in this position against the face of the grinding wheel to an extent insuring a length of this lip corresponding exactly to the length of the .lip previously ground.

When the grinding operation is completed, the wheel can be swung clear of the chuck, by grasping the knob 52 of lever 51. The drill can then be removed from the chuck, and a new drill can be positioned in the chuck to be ground. The wheel can then be swung back to operative position. For dressing the wheel will also be swung away from operating position by lever 51. In order to avoid excess wear of the grinding wheel at any point, support 30 is adjusted from time to time by adjustment of the stop pin 41 so that all parts of the face of the wheel will be used without excessive wear at any one part across the face.

While the invention has been described in connection with a specific embodiment thereof, it will be understood that it is capable of further modification, and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth, and as fall within the scope of the invention, or the limits of the appended claims.

Having thus described our invention, what we claim is:

1. A drill grinding machine comprising a base, a support mounted on said base for pivotal movement and for movement in the direction of its pivotal axis, an electric motor mounted on said support, a grinding wheel secured to the armature shaft of said motor coaxially thereof with its active face in a plane perpendicular to the axis of said armature shaft to rotate about an axis parallel to said pivotal axis, means for moving said s pport in the direction of its pivotal axis, an arm mounted on said base for angular adjustment about an axis extending in a direction at right angles to the direction f said pivotal axis, a bracket mounted on said arm for rocking movement about an axis which is inclined at other than right angles to both of the aforesaid axes, means for rigidly securing a drill to said bracket with the axis of the drill at an angle to all three of the aforesaid axes, means for rocking said bracket about its axis, and stop means adjustable on said base to limit the pivotal movement of said support in one direction at least, thereby to determine the portion of the face of said grinding wheel which contacts the workpiece.

2. A drill grinding machine comprising a base, a sup port mounted on said base for pivotal movement and for adjustment in the direction of its pivotal axis, a grinding wheel rotatably mounted on said support for rotation about an axis parallel to said pivotal axis, an arm mounted on said base for angular adjustment thereon about an axis extending at right angles to the direction of the axis of rotation of said grinding wheel, a bracket mounted on said arm for rocking movement about an axis which is inclined at other than right angles to b th the aforesaid axes, means for rigidly securing a drill to said bracket so that its axis is inclined at other than 10 right angles to all three of the aforesaid axes.

References Cited in the file of this patent UNITED STATES PATENTS 15 2,142,923 Stocking Jan. 3, 1939 2,713,755 Ganahl July 26, 1955 2,866,302 Amiet Dec. 30, 1958 

